88 KX 250

[concave3]

Whats up you all, I am new to this forum because I am now a proud owner of an 88 kx 250, I originally bought it without a piston, I just put it in and it runs and the engine sounds really strong!

But I have a carb problem it has a keihin pwk 39 with a 162 main and a 58 pilot, the only way that it starts and runs is with the gold screw all the way in and the idle screw backed out pretty good and choke on and me blowing fuel into the reeds... then it will fire up idle pretty normal then about to stall, then I tap the throttle and it revs up real good and backs down to a normal idle for about 15 seconds until it wants to die again... anybody else run into some pain in the neck problems with the pwk?

thanks for any info, nice to be a part of the forum!

[1989kawasaki]

Welcome! cool bike you got there , i got the 89 kx250 . maybe you can post a pic of yours  and i also believe that it has a PWK 38mm unless someone upgraded it

[concave3]

thanks! Ill post picks tomorrow! not to familiar with the difference between the 38 and 39 so i was taking a wild guess lol so I guess I have the 38.

[1989kawasaki]

can you tell me if the front brake caliper has 1 or 2 pistons in it? you can tell by looking at it

[concave3]

it doesn't work but it is a 2 piston, Ive tried bleeding it, I did it the same as the back but it fails to work! but yea its a 2 piston.

[concave3]

LOL I think you just watched my startup vid on youtube! this was probably my 5th start and cruise! it has a ton of power, im used to an rm125 and this things boss!!! wheelies through 3rd and tunnel vision after that lol

[1989kawasaki]

hahaha i did watch a video with an 88 kx250 in it. since you said you have a 2 piston caliper in the front that makes it an 89.
i was cat123456789101 on youtube

[concave3]

lol thats sick dude! but idk it could be a single im going off what my little bro is saying... it does look like crap, worst brake caliper ive ever seen! the ones that on its know is from an 84 and that didnt work either... it could be my master but im not sure

[1989kawasaki]

well as soon as i can see some good up close pics then i can properly tell what you have 

[Caddy 16v]

Hi,

I have a 88 as well, just take your carburetor off, take it apart and clean it really good with brake cleaner, pretty sure that your main jet and pilot jet are clogged up.

[Friar-Tuck]

 Hey CC3
 The '88 kx 250 did in fact come with the PWK 39 and the jetting specs are as follows as per the Clymer  M447-2 pg.334

Main Jet  172
slide cut-away  #7
jet needle R1368J   3rd clip position
Pilot  52
Air Screw 11/2 turns out
Float height 15-17 mm

 If You can swing it I would Highly recommend the Clymer (its usually cheaper) or a set of service manuals.
   Welcome to the site,
  Tuck\o/

[1989kawasaki]

thats odd that it came with a pwk 39.. mine came with a pwk 38

[concave3]

well I have the carb in front of me it sports a 162 main, and a 55 pilot... and I cleaned it all about a month ago and they are still clean I had just forgotten the jet sizes. the clip itself was right in the middle notch, I tried moving it down and the idle was off the wall, so I moved it one up from the middle and it helped a little. the only way that it starts is with the air screw all in or a little out and the idle screw way out... then it idles okay then it starts to die, so i tap the throttle and the rpm's go crazy, I have to use the kill switch so it doesent rev too high... any info would be great on how to keep the idle down on this beast.

[Friar-Tuck]

 89'r
 Yep that's what I see in the clymer, the '88 came with the 39 and the 89 with a 38mm. I know it seems backward, but heck anyone could've swapped out parts either way.  I think I'm the fourth owner of my 2k 500 and your bikes have a few years on mine.

 It shouldn't be a problem getting the carb tuned close, I should think.
   
 CC3,
  I know this sounds corny, but get a notebook and record your settings and jets, and keep it somewhere in the garage.
      Before I did this I was constantly buying the wrong jets.   Another thing is to see what the bike is doing as far as weather (time of year) and any other maintenance you've done.  (guys looking to buy a bike like being able to see this also when it comes time to sell)
 
  I'll look for a few links to help get you on the right track as far as what jets will get you where you want to be.
 
 The Factory has to jet the bike on the fat side to be safe,(heck they end up all over the world) and it would appear your main is lean and the pilot is fat.
I would like to make one thing clear right from the git go.
 There are a slew of variables that come into play. 
Here are just a few, Weather, Altitude,condition of the engine, modifications,type of riding, how hard the rider is working the engine, pre-mix and ratio etc-etc..  so as much as I would like to be able to say
"Oh Yea, put in a 50 pilot above 70degrees and a 52 below and run a 168main above 70 deg and 170 below and you'll be Good to Go"
  I really can't.  If you are willing to do a bit of reading and hang with us a few posts I'm sure we can get you close,
and then you'll be surprised at how simple it will be to dial her in.

Here's a link to our Gallery where posted a bunch of stuff. 
(You should be able to get the next two pages by clicking the arrow for next at top of the page.)
  http://www.kxriders.com/coppermine/displayimage.php?album=267&pos=6

  Tuck\o/

[concave3]

Well today was the first time I got it offroad and opened her up!... the bike runs absolutely perfect with the choke on
the only problem I had was the plug vibrated all the way to the last threads and when my bro was on the pipe it blew the sparkplug right out of the head I though it blew up but it was fine... I put the plug back on when I got home and it fired right up! I also got my front brakes working...

all in all I love this bike now! blows any 125 ive ever ridden away!